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For quite some time, I am reading about space adhesives. Selecting the right adhesive for space applications is extremely important, mainly due to the high vacuum (around 10-8 Torr), and the variation in temperature. A key concern is the outgassing property of these adhesives. Any outgassing might lead to contamination of electronic or optical components, which can have a drastic impact on the optical properties of the system.

  • What are the commonly used space adhesives in satellites?

  • What are the standards of adhesives to qualify as space-worthy (other than Outgassing standard test ASTM E 595 / ESA PSS-014-702)?

  • Which would be the most important requirement or trade-off of a space adhesive (withstanding wide range of temperature / UV, gamma & other radiation / lower outgassing / resistance against free radical or atomic oxygen)?

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    $\begingroup$ This ESMAT website with materials databases on outgassing, stress corrosion, galvanic corrosion, flammability,... should be useful. $\endgroup$ – TildalWave May 6 '15 at 13:34
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If you've been reading "for quite some time", you probably know much more than I do. However ...

From this general article

http://machinedesign.com/fasteners/epoxies-and-adhesives-fit-space

I found a mention of NASA's "Vacuum stability requirements of polymeric material for spacecraft application". This standard doesn't appear to have been amended since the early 1980s.

This doesn't really tell you the most commonly used space adhesives, but from the Machine Design article, it looks like lots of fairly generic epoxies pass muster.

As for tradeoffs, it probably depends on your application. If the glue won't be exposed to UV, and otherwise has nicer strength properties, it might mean you can use less of it, saving on spacecraft mass.

The book chapter here (Handbook of Adhesives and Sealants, Volume 1: Basic Concepts and High Tech Bonding. Elsevier, 2005. ISBN 9780080445540)

https://books.google.co.jp/books?id=9XFD8ZsZzAsC&lpg=PA334&ots=-oKiRMQAGm&dq=adhesives%20for%20satellite%20construction&pg=PA334#v=onepage&q=adhesives%20for%20satellite%20construction&f=false

appears to go into the different tradeoffs for space applications generally, when considering adhesives.

I hope this helps.

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The list of NASA certified space-rated epoxies is long and contains hyperlinks, so I'll show the definition and categories here, and leave the link for the actual list.

https://www.masterbond.com/certifications/nasa-low-outgassing

The industry standard test for measuring outgassing in adhesives and other materials is ASTM E595. Developed by NASA to screen low outgassing materials for use in space, the test determines the volatile content of material samples placed in a heated vacuum chamber. Samples to be tested are first preconditioned at 50% relative humidity for 24 hours and then weighed. Following this, they go into the test chamber for another 24 hours with the temperature set at 125°C and the vacuum at a minimum of 5x10-5 torr. During the time in the test chamber, volatiles that outgas from the sample escape through a port in the test chamber and condense on a cooled (25°C) collector plate. The sample and condensate on the collector plate are then weighed to determine the total mass lost (TML) by the sample and the amount of collected volatile condensable materials (CVCM) on the collector plate. Materials pass or fail the test based on these TML and CVCM measurements. If the CVCM exceeds 0.1%, the material fails. The material will also fail if the TML exceeds 1%—though the TML may be offset by water vapor regained (WVR) by the sample in a subsequent measurement:

  • If CVC <0.1% and TM < 1%, the material passes.
  • If CVC <0.1% and TM > 1 %, the material can pass if the TML-WV <1%.
  • If CVC > 0.1% or TML-WV > 1%, the material fails.
  • If a material passes NASA low outgassing tests, it can be used in a multitude of applications including outer space, high vacuum, specialty optical and electro-optical applications, among others.

Two Component Epoxy Systems: (categories)

  • Electrically Insulating
  • Electrically Insulating and Thermally Conductive
  • Electrically Conductive
  • Cryogenic
  • Optically Clear

One Component Epoxy Systems: (categories)

  • Electrically Insulating
  • Electrically Insulating and Thermally Conductive
  • Electrically Conductive
  • Cryogenic

UV Curing Systems: (categories)

  • Electrically Insulating

One Component Silicone Systems (categories)

  • Electrically Insulating

Two Component Silicone Systems (categories)

  • Electrically Insulating
  • Electrically Insulating and Thermally Conductive
  • Thermally Conductive
  • Electrically Conductive
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  • $\begingroup$ I've added some information to your answer so that there is helpful information available to future readers if/when the link breaks. In Stack Exchange it's generally recommended not to leave link-only answers. Welcome to Space! $\endgroup$ – uhoh Jan 9 at 6:06

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